Wireless Communication Method, and Wireless Communication Device and System Using the Same

1. A communication method performed by a communication device, the method comprising: receiving a message including channel information indicating a channel used by at least one external device in a frequency band assigned to the at least one external device, the frequency band including a plurality of channels; generating, by a control unit, candidate available channels in the frequency band assigned to the at least one external device based on the channel information, wherein the candidate available channels comprise at least one of a channel not used by the at least one external device, among a plurality of the channels in the frequency band assigned to the at least one external device; searching, by the control unit, for candidate available channels in a remaining frequency band that is not assigned to the at least one external device; determining, by the control unit, available channels using a combination of the generated candidate available channels and the candidate available channels from the search result; and performing communication through one of the determined available channels, wherein the receiving operation comprises receiving a message including updated channel information from the at least one external device when the channel used by the at least one external device is changed, and the generating operation updates the candidate available channels to at least one of a channel not currently used by the at least one external device based on the received message including the updated channel information, wherein the determining available channels comprises determining an available channel as a channel, from among the candidate available channels, having a longest available time based on information on the candidate available channels which changes over time, and wherein the performing communication comprises performing communication by changing a channel in use to the determined available channel.

2. The communication method according to claim 1 , wherein the receiving operation comprises receiving the channel information from the at least one external device through a channel which is not used by the at least one external device, in the frequency band assigned to the at least one external device.

3. The communication method according to claim 1 , further comprising: generating the information on candidate available channels which changes over time based on the channel information and the search results.

4. The communication method according to claim 3 , wherein the available channel is one of a plurality of available channels, and the performing communicating by changing the channel in use comprises performing communication by changing the channel in use to one of the plurality of available channels.

5. The communication method according to claim 1 , wherein the channel used by the at least one external device varies according to a region, and the receiving comprises receiving the channel information for a current region through the Internet.

6. The communication method according to claim 1 , wherein the at least one external device comprises a television (TV) or a radio.

7. A wireless communication device, comprising: a communication unit which receives a message including channel information indicating a channel used by at least one external device, in a frequency band assigned to the at least one external device, the frequency band including a plurality of channels; and a control unit which generates candidate available channels in the frequency band assigned to the at least one external device based on the channel information, wherein the candidate available channels comprise at least one of a channel not used by the at least one external device, among a plurality of the channels in the frequency band assigned to the at least one external device, searches for candidate available channels in a remaining frequency band that is not assigned to the at least one external device, determines available channels using a combination of the generated candidate available channels and the candidate available channels from the search result, and performs communication through one of the determined available channels, wherein when the channel used by the at least one external device is changed, the communication unit receives a message including updated channel information from the at least one external device, and the control unit updates the candidate available channels to at least one of a channel not currently used by the at least one external device based on the received message including the updated channel information, and wherein the control unit determines an available channel as a channel, from among the candidate available channels, having a longest available time based on information on the candidate available channels which changes over time, and sets the determined available channel as a channel to be used by the wireless communication device.

8. The wireless communication device according to claim 7 , wherein the control unit receives the channel information from the at least one external device through a channel which is not used by the at least one external device in the frequency band assigned to the at least one external device.

9. The wireless communication device according to claim 7 , further comprising: an available channel information generation unit which generates the information on the candidate available channels which changes over time based on the channel information and the search results.

10. The wireless communication device according to claim 9 , wherein the available channel is one of a plurality of available channels, and the control unit sets one of the plurality of available channels as the channel to be used by wireless communication device.

11. The wireless communication device according to claim 7 , further comprising: an Internet interface through which the wireless communication device accesses the Internet, wherein the channel used by the at least one external device varies according to a region, and the control unit receives channel information for a current region through the Internet.

12. The wireless communication device according to claim 7 , wherein the at least one external device comprises a television (TV) or a radio.

13. A wireless communication system, comprising: at least one first device which generates a message including channel information indicating a channel in use in an assigned frequency band of the at least one first device, the frequency band including a plurality of channels, and transmits the message in response to receiving a channel information transmission request; and at least one second device which transmits the channel information transmission request to the at least one first device, receives the message including the channel information, generates candidate available channels in the frequency band assigned to the at least one external device based on the channel information, wherein the candidate available channels comprise at least one channel not used by the at least one external device, among a plurality of the channels in the frequency band assigned to the at least one external device, searches for candidate available channels in a remaining frequency band that is not assigned to the at least one external device, determines available channels using a combination of the generated candidate available channels and the candidate available channels from the search result, and performs communication through one of the determined available channels, wherein when the channel in use in the assigned frequency band is changed, the at least one first device transmits to the at least one second device a message including updated channel information, and the at least one second device updates the candidate available channels to at least one of a channel not currently used by the at least one external device based on the received message including the updated channel information, and wherein the at least one second device determines the available channels as channels, from among the candidate available channels, having longest available times based on information on the candidate available channels which changes over time, and sets the determined available channels as channels to be used by the wireless communication device.